Cyclone separator



March 10, 1936. H, N N 2,033,471

CYCLONE SEPARATOR Filed Aug. 30, 1933 2 Sheets-Sheet 1 INVENTOR ATTORNEYMarch 10, 1936. J. H. KEENAN CYCLOIYE SEPARATOR Filed Aug. 30, 1933 2SheetsSheet 2 INVENTOR "ATTORNEY Patented Mar. 10, 1936 CYCLONESEPARATOR Josephll. Keenan, Hoboken, N. J., assignor to Jabez Burns &Sons, Inc., New York, N. Y., a corporation of New York ApplicationAugust 30, 1933, Serial No. 687,402

9 Claims.

This invention relates to improvements in devices for separatingparticles of denser substance from liquid or gas streams by swirling thestream and its particles in a free or constrained vortex. I shall referto all such devices, whether for completely separating particles andstream or merely for concentrating the particles within a portion of thestream, as cyclone separators.

The pressure drop through a cyclone separator is determined by the rateof change of pressure with radius and the radial distance the streammust travel between inlet and outlet. Any increase in outlet diameterfor a given cylinder diameter reduces this radial distance the streammust travel and so reduces the pressure drop, provided that noadditional pressure losses are introduced.

My invention, in a preferred form hereinafter described, includes asqueezer or spreader which spreads the stream into a tall, narrowpassage without altering appreciably the degree of uniformity ofvelocity which exists in the duct, a diffusing passage preceding theinlet to the separating chamber and an unusually large ratio ofseparator outlet diameter to separating cylinder diameter, namely,greater than 0.5. The tall, narrow stream formed by the squeezer canpass between the separating cylinder wall and the large diameter outletpipe without being restricted, consequently without causing additionalpressure losses. 7

The squeezer causes the stream to enter the separator as a sheet, thinin the radial dimension. Consequently, all of the particles to beseparated are concentrated near the separator wall and can be separatedmore easily than in existing types of separators. A larger outletdiameter may now be used and the outlet pipe may terminate adjacent oreven above the inlet opening without short-circuiting the vortex andwithout reducing the efliciency of separation below that of existingtypes of separators of the same cylinder diameter. The result is asmaller pressure drop across the collector for the same elliciency ofseparation because the stream passes through a smaller range of thevortex pressure before it is discharged.

The diffusing passage preceding the separator inlet reduces the velocityentering the separating chamber below that in the duct and utilizes theexcess duct velocity to raise the pressure at the separator inlet.Further, the lower entrance velocity causes a smaller pressure drop inthe separating vortex between the cylinder inlet and the outlet pipe.Consequently the entrance diffuser serves to keep pressure drop ordiameter or both smaller than in existing separators.

It is evident that though the squeezer, the large diameter outlet pipeand the diffuser have their respective useful functions, in combinationthey provide benefits which result from intimate interrelation of thesefunctions and which are more than the accumulation or their individualeflects.

The combination of entrance squeezer, entrance diffuser and exitdiifuser with a cyclone separator having an outlet pipe diameter-greaterthan half the separating cylinder diameter yields an extremely lowpressure drop for a high quality of separation or it permits the use ofa small cylinder diameter as compared with existing cyclone separatordesigns.

The following definitions apply to the correspending terms throughoutthese specifications and the claims that follow them:

Difiusion is the process of increasing the pressure along the path of afluid stream by reducing its velocity.

A diil'user or a diffusing passage is a passage in which diffusion isaccomplished.

A squeezer is a passage for a fluid stream of substantially uniformcross-section area in planes normal to the mean direction of streamflow, the shape of the cross-section changing from round orsubstantially squareat entrance to tall and narrow at exit; the changein shape being accomplished in such manner as not to cause a. markeddecrease in the degree of uniformity of velocity between the entranceand exit of the passage.

Separating cylinder diameter is twice the distance from the verticalline passing through the center of the outlet hole or pipe to thenearest point on the cylinder wall.

In the accompanying drawings:

Fig. 1 shows a cyclone separator with an inlet squeezer followed by adiffuser.

Fig. 2 is a plan view of the device shown in Fig. 1.

Fig. 3 shows a cyclone separator with an inlet difiuser followed by asqueezer.

Fig. 4 is a plan view of the device shown in Fig. 3.

Fig. 5 shows a cyclone separator with an inlet squeezer, an inletdiifuser and an outlet difluser.

Fig. 6 is a section along 6-6 through the device shown in Fig. 5.

Fig. 7 exhibits experimental data showing the saving realized by adevice similar to that shown in Figs. 5 and 6 over awell-designedexisting type of separator.

In Figs. 1 and 2 a cyclone separator H] has an outlet diameter greaterthan half the separating cylinder diameter and is fitted at entrancewith squeezer l I followed by diffuser [2.

In Figs. 3 and 4 the order of squeezer and diffuser is reversed. Tocyclone separator I3 is connected inlet diffuser 14 followed by squeezerl5.

In Figs. 5 and 6 is shown cyclone separator l6 fitted with inletsqueezer I! followed by diffuser i8, and, mounted on top of theseparator, exit diffuser l9.

Fig. 7 shows the substantial saving in pressure drop realized by acombination similar to the one shown in Figs. 5 and 6 (curve 20) overone of the best existing cyclone separator designs (curve 2|).

The abscissae of Fig. '7 are rate of gas flow in arbitrary units.

The invention claimed is:

l. A combination in a cyclone separator of a squeezer having an inletcross-section fitting that of the supply pipe and an outletcross-section the height of which is more than four times its width, agradually diverging diffusing passage leading to an inlet opening in thewall of the separating cylinder which is so disposed that the directionof the stream in this opening is substantially perpendicular to avertical plane passing through the center-line of the cylinder and theinlet opening, a separating cylinder, at least as tall as the inletopening communicating with a chamber below for collecting separatedmaterial and with a central outlet pipe above, the diameter of which ismore than half the cylinder diameter.

2. A combination in a cyclone separator of a gradually divergingdiffusing passage leading from the approach pipe to a squeezer, asqueezer connected to the cylinder for changing the crosssection of thediffused fluid stream from the section of the diffuser outlet to a tall,narrow crosssection, the height of which is more than four times itswidth, and an outlet pipe from the cylinder having a diameter greaterthan half the cylinder diameter.

3. A combination in a cyclone separator of a combined squeezer anddiffuser inlet passage which spreads the air stream over a tall, narrowcross-section area, the shape of the passage being such that itincreases in cross-section area so gradually in the direction of flowthat practically the entire final section of this passage is filled withfluid flowing in one direction, and an outlet pipe from the cylinderhaving a diameter greater than half the cylinder diameter.

4. A combination in a cyclone separator of a squeezer having an inletcross-section like that of the approach pipe and an outlet cross-sectionthe height of which is more than four times its width, a graduallydiverging diffusing passage leading to an inlet opening in the wall ofthe sepai'ating cylinder which is so disposed that the direction of thestream in this opening is substantially perpendicular to a plane passingthrough the center-line of the cylinder and the inlet opening, aseparating cylinder, at least as tall as the inlet opening, thiscylinder communicating with a chamber below for collecting separatedmaterial and with a central outlet pipe whose diameter is more than halfthe cylinder diameter, two substantially parallel plates supported abovethe separating cylinder, the lower of the two plates being provided witha central hole and being attached to the exit pipe of the separatingcylinder so that the hole in the plate is concentric with the exit pipeof the cylinder.

5. The combination with a separator having a cylindrical separatingchamber, an imperforate outlet pipe, a settling space, and an elongatedvertical tangential inlet, of means in advance of said inlet forsqueezing and diffusing the mixture to be separated.

6. A cylindrical separating chamber adapted to confine a tall narrowcircumferential vortex of gas and dust having an outlet pipe having itsperiphery closed, and an inlet passage of uniforr l cross-sectional areashaped at the one end for connection to a pipe and having a tall narrowopening at the inner end, a diffusing passage connected thereto andtangentially to said chamber to admit dust laden gas to said chamber ina tall narrow stream at reduced velocity, said gas outlet being disposedcentrally of said chamber.

7. In combination, an inlet pipe for carrying mixed dust and gas, meansconnected therewith for converting and squeezing said mixture into arelatively tall and narrow stream of greater area than that of the inletpipe and of substantially uniform velocity, a cylindrical separatorhaving an inlet tangentially receiving said stream to whirl same anddeposit dust, a central gas outlet pipe having its periphery closed foradmitting outlet gas at its bottom, and an outlet diffuser connected tothe outer end of said outlet pipe.

8. The combination with a separator having a cylindrical separatingchamber, an imperforate outlet pipe, at settling space, and an elongatedvertical tangential inlet, of means in advance of said inlet forsqueezing and diffusing the mixture to be separated, and an outletdiffuser connected to the outer end of said outlet pipe.

9. In combination, an inlet pipe for carrying mixed dust and gas, meansconnected therewith for converting and squeezing the mixture into arelatively tall and narrow stream, a cylindrical separator having aninlet tangentially receiving the stream to whirl it and deposit dust, acentral gas outlet pipe and an outlet diffuser connected to the outerend of the outlet pipe.

JOSEPH H. KEENAN.

